I/O-LED 1-2

Unknown data type (Fault code 1, argument 2)

Wago · Modular I/O System PROFIBUS DP

What does I/O-LED 1-2 mean?

The Fieldbus Coupler has encountered an unknown or unsupported data type during its operation or initialization process. This suggests a fundamental configuration error or a hardware fault preventing proper data interpretation by the coupler's firmware.

Common Causes

  • Incorrect or unsupported data type specified in the coupler's configuration
  • Hardware defect within the coupler causing misinterpretation of data structures

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Replace the Coupler.

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Verified technical data. Last updated: March 2026

Related Faults

I/O-LED 1-4Fault during writing into the flash memory (Fault code 1, argument 4)BUS-LED 3-1Insufficient configuration data (Fault code 3, argument 1)BUS-LED 4-nConfiguration byte (module) n is faulty (Fault code 4, argument n)
Source: Wago Modular I/O System PROFIBUS DP
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